Hull shape and a method of drawing a hull of said shape



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N. J. MALMEERG Filed May 2, 1961 HULL SHAPE AND A METHOD OF DRAWING A HULL OF SAD SHAPE Nov. 24, 1964 United States Patent O 3,158,125 HULL SHAPE AND A .METHOD F DRAWING A HULL F SAID SHAPE Nils .iohan Malmberg, Caloninsgatan dAS, Helsingsfors, Finland Filed May 2, ll, Ser. No. t',166 Claims priority, application Finland, May 2, 1960, 7'7l/ 6l) 2 Claims. tCl. 13A-56) The present invention relates to building of vessels and boats. More particularly, the present invention relates to a hull the surface of which has a special shape, and, further, it relates to a method of designing or drawing a hull of said shape.

lt is common that vessels, which are designed to be plated with metal sheets, plywood or sheets of other materials, have been shaped in such a way that the frames are designed using straight lines, in order to make it possible to carry out the plating work using single curved sheets instead of double curved sheets. This makes the plating work easier, of course, but has the drawback that the shape of the vessel becomes less nice looking and ungainly. These hull shapes are very common, especially in connection with small wrapped plane bottom vessels or the so-called V-bottom boats. When in such boats the sheets to form the bottom between the keel and the chine are bent, said sheets have the tendency to take a convex or concave frame shape, although the bottom part of the boat has been shaped with straight frame lines. This tendency has been used by many boat builders in order to get soft bottom lines. The side surfaces, i.e. the surfaces between the railing and the chine at the most are liked to be shaped using concave frame lines. So far, however, one has not succeeded in sheathing side surfaces having concave frame shapes using single curved whole or monolithic plates or sheets. Therefore such boats having concave frame shapes of the side surfaces are plated either using slender planks or double curved sheets and plates as for instance in the common ships building. Previously tests have been made in order to compose hull surfaces using elements forming parts of cylinders and cones, however, without any practical success.

From the geometry there are known curved surfaces of such a kind that through a point located in the surface a straight line can be drawn, which completely is included into said surface. This invention makes use of this property for the forming of hulls for boats and ships in such a way that also concave or convex side surfaces can be plated using single curved plates, although the frame lines are curved according to a chosen curvature. One of the advantages connected to this invention is the bigger freedom the designer has when forming the hull instead of the previous method using straight frame lines, In the following description the sentence frame section means a plane, which in the usual manner is in a 90 angle at both the water line planes and the centre plane, the latter being the vertical plane along the` keel line. The used expression double curved surface indicates a surface of such a shape as for instance a sphere, While the cylinder for instance represents a single curved surface, The frame line, of course, is the intersectional line between the frame plane and the hull surface. One of the embodiments of the invention consequently is a hull surface, preferably the whole hull side, which is of such a shape that it intersects the frame planes in curved lines. Additionally it is bent to connect to the curved railing line and chine in the length direction of the vessel over straight lines included in the hull surface, which is single curved according to said intersectional lines between the hull surface and the frame 3,l5,l25 Patented Nov. 24, 1964 lCe planes, and which straight lines have an inclination in relation to the frame planes depending upon the curvature of the railing line andthe chine.

Another aim of the invention is also to disclose a method to be used in the designing work in order to determine said inclined straight lines in such a way that they are laying in the single curved hull surface chosen according to the frame curvature. The intersectional points of the straight lines with the railing line and the chine thereafter can be correctly marked on the hull side plate or sheet and this thereafter easily can be bent over these straight lines to connect with the railing line and the chine. A single whole or monolithic side sheathing formed according to this method therefore as a matter of fact easily can be formed as a single curved surface in spite of the curved frame line, which makes the work at the shipyard considerably easier than before.

In the following description there is disclosed more in detail an embodiment of the invention, thus disclosing how the design work can be carried out in order to fix the location of the straight lines laying in the hull side and over or along which the hull plate, in spite of the curved frame line, has to be bent in order to get the sheet single curved across the direction of said lines. As an example there has been chosen the side of a V-bottom boat.

In order that the present invention may be readily carried into effect, it will now be described with reference to the accompanying drawing, wherein:

FIG. l is a side view of an embodiment of the hull surface of the present invention;

FIG. 2 is a bottom view of the embodiment of FIG. 1;

FIG. 3 is a front view of the embodiment of FIG. 1.

In designing the hull, the designer selects, as usual, the desired curvature of the frame line, and must then ix different points of the straight lines between the railing and the chine, over'which lines the hull plate has to be bent. Some of these lines have been marked on the drawing in using the marking 11 to 120. The hull consequently has to be formed in such a way that from the railing always can be drawn against the frame planes inclined straight lines, for instance the lines l1 to 120, which are laying in the hull surface. According to this method a plate of plywood sheet can be bent to the hull shape along the bending lines 11 to 120 without becoming double curved. The geometrical condition for a straight line to be ineluded in the hull surface is that the distance from an intersectional point on the straight line with an assumed water line of the hull surface has the same distance from the centre plane f-g in FIG. 2 as well as in FIG. 3. In order to determine the hull shape with a suicient accuracy for ships building, it is enough to determine the intersectional lines of the hull with a relatively small number of frame and water lines. In the drawing there has been determined the intersectional lines ofthe hull with the frame planes 0 9 and the Water line planes w11 to w14. When designing the hull shape of the boat, the frame lines and water lines are adapted to each other in the common way. In order to get the hull shape to meet the requirements according to this invention the inclined straight lines 11 to 120 have to be adjusted to the frame lines as well as to the Water lines. In this case all the straight lines 11 to 12o have been adjusted to the frame lines -a and the water lines w11 t'o w14 in the same way as the line 118 chosen as an example. The distance h from the centre plane f-g to the -intersectional point c V(located in the water line plane) between 118 and w13 is the same in FIG. 2 and FIG. 3. This means that the point' c is laying in the hull surface. In the same way the distance of the intersectional point b of the line 113 and w14 from the centre plane f-g is the same in FIG. 2 and FIG. 3. When the line 118 crosses the railing line and the chine, and when for instance the two therebetween located points b and c lie in the huil surface, the whole line 118 lies in the hull surface completely to meet all practical requirements. In the same manner all the other straight lines 11 to 120 have been adapted bothto the frame lines -9 as well as to the Water lines w11 to wigand consequently all these lines are included to their Whole length in the hull surface. A further control measure in order to Vget assured that for instance the point c Will be in the hull surface consists therein that the point c is laying on the-same drawn vertical line c-c between FIG. l and FIG. 2. Just in the same Way the intersectional point b and all other intersectional points between the other linesll to 120 and the water lines w11 to w14 are on the corresponding vertical lines between FIG. 1 and FIG. 2.

Apart from the above the adapting of the frame lines 0 9, Water lines w11 to w14 and the lines 11 to 120 to each other can be managed in such a way that the angles al to x20 continuously change, these angles being those under which the extensions of the lines 11 to 12 are crossing an arbitrary line z'-j. This has been made in the'same manner for all the lines 11 tolgo as for the line 118. From the intersectional point k between the extension of the line 118 with the line z'j there has been determined aperpendicular distance k-l, which chosen in a convenient length measure, for instance millimetres, numerically corresponds to the degree number of the angle uw. The same operation preferably to be carried out at the tore, mid and stern part or" the hull. Through the points determined in this Way it is possible to draw a curve rit-11, which discloses that the angles bet-Ween the lines 11 to 120 and the frame planes continuously andsxnoothly change.

On the other hand, if towards the line j a perpendicular line is drawn, the part being between the line z'-j and the curve m-n, for instance the part kel, numerically indicates the degree figure of the corresponding angle of inclination e.g. x18 against the frame planes i.e. they angle of the straight line, e.g. 118, which is laying .in the hull surface and the extension of which crosses the line i-j in its intersectional point with for instance the line k-l In this Way the location of for instance the line 116 easily can be determined in such a Way that from ya point o on the line i-j the perpendicular distance o-p is measured, whereafter the angle als, the degree `number of which numerically corresponds to the distance o-p, will be drawn through the point o. In the same Way consequently an indenite number of inclined straight lines can be drawn close to each other through each point .of the hull surface so that said lines surely are included in the hull surface, which on the other hand means that in the Whole surface there are included straight lines from the railing to the chine and which, as said, are laying in the hull surface. Because of that the hull surface as a Whole can be bent over said straight bending-lines. This also means that the hull surface completely can be sheathed using a sole single curved sheet fronrthe fore part to the stern part of the boat.

It is understood that the hull need not necessarily be completely Vshaped according to the invention and, consequently, if desired only certain parts of the hull surface, such as, for example, the fore part of a ship, may be shaped according to the invention.

What is claimed as new and desired to be secured by Letters Patent is:

1. A hull surface having a bow portion, a stern portion and a keel portion extending from said bow portion to said `stern portion, a center pla-ne extending substantially vertically through said keel portion, -a-plurality of frame planes intersecting said center plane at right angles, a chine and a railing, said hull surface `comprising a single curved surface including a plurality of straight lines Wholly within said curved surface extending from said chine to said railing at an inclination t'o said framevplanes, said single curved surface intersect-ing said frame planes in curved lines and being bent at said plurality of straight lines to connect said chine with said rail.

2. A hull surface having a bow portion, a stern portion and a-keel portion extending from said bow portion vto saidstern portion, a center plane extendingsubstantially vertically through said keel portion and a plurality of frame planes intersecting said center plane at right angles, said'hull surface comprising a single curved surface including a plurality of straight lines wholly Within said curved surface at an inclination -to said-frame planes,V

said single curved surface `intersecting said -frarne planes in curved lines and being bent at said plurality of straight lines.

References lited yin the -iile of this patent UNITED STATES PATENTS 2,288,490 Scott-Paine June 310, 1942 2,915,031 Johnston Dec. 1, 1959 3,040,687 -Huet June 26, 1962 FOREIGN PATENTS 809,325 Great Britain Feb. 25, 1959 OTHER REFERENCES v Engineering Descriptive Geometry, pages 12, 3l, 32, 146, 152 and 153, Charles Elmer Rowe (1943), D. Van Nostrand Co. Inc. 

1. A HULL SURFACE HAVING A BOW PORTION, A STERN PORTION AND A KEEL PORTION EXTENDING FROM SAID BOW PORTION TO SAID STERN PORTION, A CENTER PLANE EXTENDING SUBSTANTIALLY VERTICALLY THROUGH SAID KEEL PORTION, A PLURALITY OF FRAME PLANES INTERSECTING SAID CENTER PLANE AT RIGHT ANGLES, A CHINE AND A RAILING, SAID HULL SURFACE COMPRISING A SINGLE CURVED SURFACE INCLUDING A PLURALITY OF STRAIGHT LINES WHOLLY WITHIN SAID CURVED SURFACE EXTENDING FROM SAID CHINE TO SAID RAILING AT AN INCLINATION TO SAID FRAME PLANES, SAID SINGLE CURVED SURFACE INTERSECTING SAID FRAME PLANES IN CURVED LINES AND BEING BENT AT SAID PLURALITY OF STRAIGHT LINES TO CONNECT SAID CHINE WITH SAID RAIL. 